A conventional smart phone requires a human to enter a correct password (e.g., an expected sequence of numbers) before unlocking the touch screen. Once the human enters the correct password, the touch screen of the smart phone unlocks, and the human is able to operate the smart phone (e.g., the human is able to make a cellular call, launch and operate apps, etc.).
Once the touch screen is unlocked, the smart phone monitors touch screen activity and automatically re-locks the touch screen if the touch screen remains inactive for a predefined period of time (e.g., five minutes). As a result, if the human leaves the smart phone unattended for that period of time, the smart phone automatically re-locks the touch screen rather than allow the smart phone to remain in the unlocked state where it would be vulnerable to a malicious person.